去甲肾上腺素对___ 受体有强大的激动作用,对心脏β1受体作用较弱,对β2受体几乎没有作用。
You can _____ some bottles of wine, or some chocolates, or a bunch of flowers.
A campus emergency ______ occur at any time of the day or night, weekend, or holiday, with little or no warning.
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